Year Percent change (Units) 1980 16.100 1981 7.700 1982 5.486 1983 6.311 1984 5.442 1985 4.491 1986 6.607 1987 -10.211 1988 1.135 1989 5.609 1990 3.951 1991 6.077 1992 4.217 1993 6.109 1994 4.000 1995 4.100 1996 -1.667 1997 2.554 1998 3.668 1999 1.755 2000 0.377 2001 6.002 2002 3.176 2003 1.633 2004 -0.740 2005 -0.351 2006 -0.997 2007 3.578 2008 13.665 2009 9.816 2010 -3.900 2011 1.497 2012 -3.046 2013 -1.488 2014 2.104 2015 0.572 2016 1.917 2017 0.356 2018 0.564 2019 -1.813 2020 2.553 2021 2.054 2022 5.346 2023 9.277 2024 4.469 2025 3.000 2026 2.500 2027 2.000 2028 1.900 2029 1.800